1. Field Of The Invention
The invention relates to transportation vehicles and more specifically to an improved dolly for use with multiple bottom trailers
2. Description Of The Prior Art
The development of multiple bottom trailers requires the use of a dolly to support the front end of the second and subsequent trailers. Multiple bottom trailers in the context of this patent application means an arrangement in which a single tractor is used to tow two or more trailers.
Additionally, the development of multiple bottom trailers further complicates the concerns associated with maneuvering such vehicles in relatively confined spaces. These difficulties are primarily associated with the inability of the multiple bottom trailers to be steered as they are propelled backwards. These characteristics makes it necessary to frequently decouple the second and subsequent trailers from the tractor permitting each of the trailers to be moved individually.
Typically, trailer dollys have utilized only one axle and when the dolly was disconnected from the tow bar, the tongue of the dolly rotated about the axle and contacted the ground. This created considerable inconvenience in that typically the tongue weight of the dolly is in the neighborhood of 200 pounds. In order to reattach the dolly to the draw bar it was necessary to raise and support the tongue of the dolly while the towing vehicle and the dolly were being coupled together.
A typical prior art trailer dolly utilized a tongue jack attached to the frame of the trailer dolly. The tongue jack was manually positioned up and down along a fixed path to position the tongue jack in the tongue support and in the trailer use positions. Such tongue jacks must be designed to provide sufficient operating range to conveniently clear obstacles routinely encountered by such trailers and to support the tongue of the dolly in the desired position. Even if the prior art tongue jacks are designed to provide sufficient operating range, they are inconvenient to use in that a typical prior art tongue jack required considerable manual effort to move it between the trailer use and the dolly tongue support positions.
No prior art search was made prior to preparing this patent application. The above description of the prior art is based on information provided by the inventor.